Like a desert mirage, this National Natural Landmark rises huge out of the barren, immense flatness of Oregon's high desert. An enormous near-circle of towering jagged rock walls make it seem like a fort. Hike around and you'll soon realize it's even bigger than it looks! It's an old tuff ring set in what was a shallow sea in prehistoric times. As you walk around inside, imagine the early American Indians who canoed to and from what was then an island. Sandals found in a nearby cave are the oldest ever discovered, dating back around 9,000-13,000 years.